Adjustable strap buckle



July 4, 1967 w. M. JONAS 3,328,856

STABLE STR BUC LE Filed March 18, 1965 INVENTOR WALTER M. JONAS /ATTORNEY United States Patent Filed Mar. 18, 1965, Ser. No. 440,776 9 Claims. (Cl. 24191) This invention relates generally to buckles, and more particularly is directed to buckles for adjustable shoulder strap assemblies of the kind that are usually employed on Womens garments, such as, brassieres, slip and the like.

Adjustable shoulder strap assemblies of the described character include an elongated web or tape of any of a variety of different fabrics forming the strap itself and having one of its ends attached to the top of the garment, usually at the back of the latter, a buckle through which the other end of the strap is :adjustably threaded for varying the effective length of the strap assembly, and a tab or anchor in the form of a relatively short length of a fabric web or tape similar to the material of the strap and which is passed through an opening or slot of the buckle and stitched or otherwise permanently secured to the top of the garment at the front of the latter for securing the buckle to the garment. Originally, the buckles of the described shoulder strap assemblies were stamped or otherwise made of metal and coated with enamel or the like to prevent rusting and to improve the appearance of the buckle. However, during repeated laundering, the enamel coating frequently chips and thereby mars the appearance of the buckle as well as exposing the latter to rusting or corrosion.

Although numerous attempts have been made to form buckles for adjustable shoulder straps of the kind referred to above from plastic materials, rather than from metal, so as to obtain the chip-free and cost saving benefits of plastics, it has been found that those plastics having suitable rigidity and strength to permit the substitution thereof for metal in the forming of the buckles, permit slipping of the strap through the openings or slot of the buckle, particularly when the strap is formed of a smooth or slick material, such as, satin, so that the wearer is subjected to the annoyance of having to frequently readjust the effective length of the strap assembly.

Accordingly, it is an object of this invention to provide an adjustable shoulder strap buckle formed of a suitably rigid plastic material for convenient and inexpensive manufacture, and which positively locks the strap in adjusted position relative to the buckle so as to prevent slippage of the adjusted shoulder strap whether the latter is lightly or heavily loaded.

Another object is to provide a buckle capable of securely gripping a strap made of any of a variety of diiferent fabrics.

In accordance with an aspect of this invention, a buckle for an adjustable strap comprises a plastic frame having a first lateral slot adjacent one end of the frame and a second lateral slot in the frame separated from the first slot by a lateral bar therebetween so that a strap threaded forwardly through the first slot from said one end of the buckle and then rearwardly through the second slot extends across the bar at the front of the latter, and a plastic locking member pivotally mounted on the frame to swing relative to the latter about a lateral axis adjacent said one end of the frame between a forwardly projecting released position and a locked position where the locking member lies against the front of the frame, such locking member having first and second laterally directed projections or rearwardly thickened portions which are spaced apart by a distance substantially equal to the width of the bar separating the two slots of the frame and extending rearwardly into the first and second slots, re-

spectively, in the locked position of the locking member so that the strap threaded through the slots is gripped between the projections of the locking member and the bar of the frame in the locked position of the locking member.

In a preferred embodiment of the invention, the arrangement for pivotally mounting the locking member on the frame consists of a bar, preferably of circular crosssection, extending across one end of the frame, and a groove of similar cross-section formed in the corresponding end edge surface of the locking member, such groove having a relatively restricted opening extending therealong so that the end bar of the frame is releasably retained in the groove.

A further object of the invention is to provide a buckle of the described character which tends to increase the security with which the strap is gripped by the buckle in response to increased loading of the strap.

The above, and other objects, features and advantages of the invention, will be apparent in the following detailed description of an illustrative embodiment thereof which is to be read in connection with the accompanying drawing, forming a part hereof, and wherein:

FIG. 1 is a front elevational view of an adjustable strap assembly having a buckle in accordance with the present invention, which buckle is shown with its locking member partly broken away;

FIG. 2 is a sectional view taken along the line 2-2 on FIG. 1, but on an enlarged scale;

FIG. 3 is a view similar to that of FIG. 2, but showing the locking member of the buckle in its released position;

FIG. 4 is a front elevational view of the frame forming part of the buckle in accordance with this invention;

FIG. 5 is a back elevational view of the locking member of the buckle in accordance with this invention; and

FIG. 6 is a fragmentary sectional view of the buckle, but on a greatly enlarged scale.

Referring to the drawing in detail, and initially to FIG. 1 thereof, it will be seen that an adjustable shoulder strap buckle embodying the present invention, and there generally identified by the reference numeral 10, includes a frame 11 and a locking member 12 each molded or otherwise formed of a rigid plastic material. The rigid plastic material employed is preferably Delrin, that is, superpolyoxymethylene having a molecular weight of at least 15,000, but other rigid plastic materials such as, linear polyethylene, nylon, polypropylene and polyurethane may also be used for the buckle.

As shown on FIG. 4, the frame 11 of the buckle includes spaced apart side members 13 extending parallel to each other and connected, at their ends, by transverse connecting bars 14 and 15. The sides 13 of the frame are further connected, intermediate their ends, by a transversely extending intermediate bar 16 so that a first laterally extending slot 17 is defined between bars 14 and 16, and a second laterally extending slot 18 is defined between bars 15 and 16. As shown particularly on FIGS. 2, 3 and 6, the lateral bar 14 at one end of the frame is preferably of circular cross-section, while the intermediate bar 16 is of rectangular cross-section and preferably has sharp corner edges.

The locking member 12 is generally rectangular, as shown on FIG. 5, with a width approximately equal to the length of the slot 17 of frame 11. Locking member 12 has a rearwardly thickened end portion 19 with a groove 20 extending along, and opening at its end edge surface 21. The groove 20 has a cross-section that is slightly more than semi-circular with a diameter substantially equal to that of the bar 14 of frame 11 so that the groove 20 has a restricted opening at the surface 21 through which the bar 14 can be forced by reason of the inherent resiliency of the plastic material forming the frame 11 and locking member 12. When the bar 14 is received in groove 20 and held in the latter by the restricted opening of the groove, the locking member 12 is thereby pivotally mounted on the frame 11 for swinging about a lateral axis between a forwardly extending released position, shown on FIG. 3, and a locked position where the locking member 12 lies against the front of the frame, as shown on FIG. 2.

The relatively thick end portion 19 constitutes a rearward projection having an inner surface 22 opposed to its end edge surface 21, and the portion 19 is dimensioned between its surfaces 21 and 22 so as to extend rearwardly in the slot 17 of frame 11 when the locking member is in its locked position (FIGS. 2 and 6). As shown particularly on FIG. 6, the surface 22 includes a convex portion 23 extending from the back surface 24 of portion 19. Surface portion 23 has its curvature concentric with the axis of groove 20 and the radius of such curvature, indicated at 25 on FIG. 6, is approximately equal to the distance from the center of bar 14 to the surface of intermediate bar 16 extending along slot 17. The surface 22 further has an undercut or concave portion 26 which is disposed forwardly of surface portion 23 in the locked position of the member 12. Thus, in the locked position of member 12, surface 22 of end portion 19 is closest to intermediate bar 16 at the edge corners 27 and 28 of the latter.

In accordance with this invention, the locking member 12 of buckle further has a rearwardly directed projection 29 extending thereacross and spaced from the thick end portion or rearward projection 19 so that a cavity 30 is defined at the back of the locking member between projections 19 and 29. Such projections are located so that the intermediate bar 16 of frame 11 is received in cavity 30 and the projection 29 of the locking member extends rearwardly in slot 18 of the frame when the locking member is in its locked position, as shown on FIGS. 2 and 6. The surface 31 of projection 29 which faces toward surface 22 of projection 19 is preferably undercut or concave, as shown particularly on FIG. 6, so that, when looking member 12 is in its locked position, the closest approach of surface 31 to intermediate bar 16 occurs at the adjacent edge corners 32 and 33 of the latter. The thickness of projection 29 is substantially less than the distance across slot 18 between bars and 16 so that, even when locking member 12 is in its locked position, and thus has its projection 29 extended into slot 18, the lower portion of slot 18 remains open or clear, as shown particularly on FIG. 2.

The above described buckle 10 is intended to be assembled together with an anchor or tab 34 and with an adjustable strap 35, as shown on FIGS. 1, 2 and 3. The tab 34 is in the form of a relatively short length of a web or tape of any of a variety of difierent fabrics passed through the slot 18 of frame 11 and looped about the bar 15, with the ends of the tab 34 being stitched or otherwise secured to the top of a brassiere, slip or other garment, preferably at the front thereof, to form the means by which buckle 10 is secured to the garment. T-he strap 35 is in the form of an elongated web or tape of a suitable fabric which may be the same or different from the material of the tab 34 and has one of its ends stitched or otherwise permanently secured to the top of the garment, usually at the back of the latter. The other or free end portion of strap 35 is threadably engaged with buckle 10, as shown on FIGS. 2 and 3, so as to permit adjustment of the effective length of the assembly constituted by the buckle 10, tab 34 and strap 35.

When threading or lacing the strap 35 through the frame 11 of the buckle, locking member 12 is moved to its released position (FIG. 3) and the strap 35 is passed downwardly in back of the top bar 14 of the frame and then forwardly through the upper slot 17, whereupon the strap is passed downwardly in front of the intermediate bar 16 and then rearwardly through the lower slot 18. It will be apparent that, so long as looking member 12 is in its released position, the strap 35 can slip freely through slots 17 and 18 for adjusting the position of the buckle frame 11 along the strap and thereby varying the effective length of the strap assembly. However, when member 12 is moved to its locked position (FIG. 2), the strap 35 is securely gripped between the frame 11 and locking member 12, particularly between surfaces 22 and 31 of the locking member and edge corners 27 and 32, respectively, of intermediate bar 16 of the frame. It-will be seen that an upward pull exerted on the strap 35, as indicated at P on FIG. 2, imposes an upwardly directed force acting on locking member 12 in the region of the portion 23 of surface 22, that is, in a plane lying in back of the center of frame bar 14 which constitutes the pivoting axis of the locking member. Thus, the upwardly directed pull P tends to pivot locking member 12 in the' clockwise direction, as viewed on FIG. 2, that is, in the direction from its released position towards its locked position. Any turning of locking member 12 relative to frame 11 as a result of the pull P merely serves to increase the security of the gripping action on the strap between the front edge corners 28 and 33 of intermediate bar 16 and the adjacent surfaces 22 and 31, respectively, of the locking member. Thus, the pull P cannot elfect opening of the buckle 1t) and merely serves to increase the gripping action of the buckle on the strap.

One of the difficulties in producing a satisfactory plastic buckle has been the inherent resiliency of the available plastic materials. Thus, the pull P exerted on strap 35 tends to increase the length of sides 13 of the frame between bars 14 and 16, and thereby tends to increase the clearance between the surface 22 of the locking member and corners 27 and 28 at the top of bar 16. However,

at the same time, any increase in length of sides 13 would tend to reduce the clearance between surface 31 of projection 29 and the edge corners 32 and 33 at the bottom of bar 16. Thus, any reduction in the force or security of the grip on the strap at the top edge corners of bar 16 is counteracted by increasing security of the gripping action on the strap between the bottom edge corners of bar 16 and projection 29 of the locking member.

It will also be noted that the pull P, in acting upwardly on locking member 12, tends to urge the bar 14 against the bottom of groove 20 so that the load applied to the buckle cannot effect disengagement of locking member 12 from its pivotal connection with frame 11.

It is to be noted that the arcuate' rearmost portion 23 of surface 22, having a radius of curvature from the center of bar 14 substantially equal to the distance from the center of bar 14 to the surface of :bar 16 which extends along slot 17, lies in back of bar 16 when locking member 12 is in its locked position. Thus, the fabric of the strap 35 interposed between bar 16 and projection 19 of the locking member will resist swinging movement of member 12 from its locked position toward the released position even when the pull on strap 35 is relaxed. When it is desired to move locking member 12 to its released position, thereby to permit adjustment of the effective length of the strap assembly, the bottom of free end edge 36 (FIGS. 2 and 3) of the locking member is gripped, as by a finger nail engaged thereunder, and pulled forwardly and upwardly against the resistance of the interference inter-posed by the fabric of the strap between surface .portion 23 and bar 16.

Although an illustrative embodiment of the invention has been described in detail herein with reference to the accompanying drawing, it is to be understood that the invention is not limited to that precise embodiment, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention, except as defined in the appended claims.

What is claimed is:

1. A plastic buckle adjustable along a strap comprising a frame having a first lateral slot adjacent one end of the frame to define a first bar extending across said one end of the frame and a second lateral slot spaced from said first slot to define an intermediate bar therebetween, so that a strap threaded forwardly through said first slot from said one end of the frame and then rearwardly through said second slot extends over said intermediate bar at the front of the latter; and

a locking member having a groove extending along and opening at one end edge of the locking member and receiving said first bar of the frame to mount said locking member for swinging relative to the frame between a forwardly projected released position and a locked position wherein said locking member lies against the front of said frame, said locking member having first and second projections extending laterally thereacross and spaced apart by a distance substantially equal to the width of said intermediate bar, said first and second projections being located and dimensioned to extend rearwardly into said first and second slots in said locked position so that the strap threaded through said slots is gripped between said projections and intermediate bar in the locked position of the locking member, and loading of the buckle tending to move the locking member toward said one end of the frame serves to further urge said first bar into said groove.

2. A plastic buckle as in claim 1, wherein said first bar is of substantially circular cross-section and said groove has a mating cross-section which is slightly more than semi-circular so as to retain said first bar in said groove.

3. A plastic buckle as in claim 1, wherein said first projection has an under-cut surface facing toward said second projection so that swinging of said locking member from its locked position tends to decrease the clearance between said first projection and said intermediate bar at the back surface of the frame.

4. A plastic buckle as in claim 1, wherein the axis about which said locking member is swingable relative to the frame is offset forwardly relative to the back surface of said first projection in said locked position of the locking member so that a pull on the strap in the direction toward said one end of the frame tends to urge said locking member to swing toward said locked position.

5. A plastic buckle adjustable along a strap comprismg a frame having a first lateral slot adjacent one end of the frame to define a first bar extending across said one end of the frame and a second lateral slot spaced from said first slot to define an intermediate bar therebetween, so that a strap threaded forwardly through said first slot from said one end of the frame and then rearwardly through said second slot extends over said intermediate bar at the front of the latter; and

a locking member including a relatively thick end portion with a groove extending along its end edge surface to receive said first bar and thereby mount said locking member on said frame for swinging relative to the latter between a forwardly directed released position and a locked position wherein said (locking member lies against the front of said frame and has said thickend portion projecting rearwardly in said first slot, said thick end portion having an inner surface opposed to said end edge surface and closely approaching said intermediate bar in said locked position, and a projection extending laterally across said locking member at the back of the latter in said locked position, said projection being spaced from said inner surface of the thick end portion to engage in said second slot and closely approach said intermediate bar in said locked position so that the strap threaded through said slots is gripped by said inner surface of the thick end portion and by said projection against the opposite sides of said intermediate bar.

6. A buckle as in claim 5, wherein said inner surface of the thick end portion and the confronting surface of said projection are undercut.

7. In a garment fastener adjustable along a strap, the combination of a plastic frame having a first lateral slot adjacent one end of the frame and a second lateral slot in the frame separated from said first slot by an intermediate lateral bar, so that a strap threaded forwardly through said first slot from said one end of the frame and then rearwardly through said second slot extends across said intermediate bar at the front of the latter, said frame further having an end bar of circular cross-section at the side of said first slot remote from said intermediate bar; and

a plastic locking member including a rearwardly thickened portion at one end having a groove extending along and opening at the end edge surface of said locking member at said one end thereof, said groove having a cross-section mating that of said end bar and being slightly more than semi-circular, said end bar being engaged and retained in said groove to mount said locking member for swinging about said end bar of the frame between a forwardly projected released position and a locked position wherein said locking member extends from said end bar across said intermediate bar in front of the latter, said thickened end portion being dimensioned to extend rearwardly through said first slot in said locked position of the locking member and having an inner surface opposed to said end edge surface and closely approaching said intermediate bar in said locked position to clamp the strap therebetween, and the axis about which said. locking member is swingable relative to the frame being offset forwardly, in said locked position, from a part of said inner surface of the thickened portion which is at the maximum radial distance from said axis so that initial swinging of said locking member away from its locked position tends to 'decrease the clearance between said inner surface and said intermediate bar and thereby prevents inadvertent swinging of the locking member from said locked position to said released position.

8. A garment fastener according to claim 7, wherein said axis is offset forwardly relative to the back surface of said thickened end portion in said locked position of the locking member so that a pull on the strap in the direction toward said one end of the frame tends to urge said locking member to swing toward said locked position.

9. A garment fastener according to claim 7, wherein said locking member further has a projection extending laterally across said locking member at the back of the latter in said locked position, said projection being spaced from said inner surface of the thickened end portion to engage in said second slot and closely approach said intermediate bar in said locked position so that the strap is also clamped between said projection and said intermediate bar.

References Cited UNITED STATES PATENTS 460,721 10/1891 Parker 24-185 555,946 3/1896 Gaillard 24246 1,424,209 8/1922 Pabst 24-2 43 2,258,605 10/ 1941 Garth 24245 3,177,550 4/1965 Borgeson 24-245 WILLIAM FELDMAN, Primary Examiner.

E. SIMONSEN, Assistant Examiner. 

1. A PLASTIC BUCKLE ADJUSTABLE ALONG A STRAP COMPRISING A FRAME HAVING A FIRST LATERAL SLOT ADJACENT ONE END OF THE FRAME TO DEFINE A FIRST BAR EXTENDING ACROSS SAID ONE END OF THE FRAME AND A SECOND LATERAL SLOT SPACED FROM SAID FIRST SLOT TO DEFINE AN INTERMEDIATE BAR THEREBETWEEN, SO THAT A STRAP THREADED FORWARDLY THROUGH SAID FIRST SLOT FROM SAID ONE END OF THE FRAME AND THEN REARWARDLY THROUGH SAID SECOND SLOT EXTENDS OVER SAID INTERMEDIATE BAR AT THE FRONT OF THE LATTER; AND A LOCKING MEMBER HAVING A GROOVE EXTENDING ALONG AND OPENING AT ONE END EDGE OF THE LOCKING MEMBER AND RECEIVING SAID FIRST BAR OF THE FRAME TO MOUNT SAID LOCKING MEMBER FOR SWINGING RELATIVE TO THE FRAME BETWEEN A FORWARDLY PROJECTED RELEASED POSITION AND A LOCKED POSITION WHEREIN SAID LOCKING MEMBER LIES AGAINST THE FRONT OF SAID FRAME, SAID LOCKING MEMBER HAVING FIRST AND SECOND PROJECTIONS EXTENDING LATERALLY THEREACROSS AND SPACED APART BY A DISTANCE SUBSTANTIALLY EQUAL TO THE WIDTH OF SAID INTERMEDIATE BAR, SAID FIRST AND SECOND PROJECTIONS BEING LOCATED AND DIMENSIONED TO EXTEND REARWARDLY INTO SAID FIRST AND SECOND SLOTS IN SAID LOCKED POSITION SO THAT THE STRAP THREADED THROUGH SAID SLOTS IS GRIPPED BETWEEN SAID PROJECTIONS AND INTERMEDIATE BAR IN THE LOCKED POSITION OF THE LOCKING MEMBER, AND LOADING OF THE BUCKLE TENDING TO MOVE THE LOCKING MEMBER TOWARD SAID ONE END OF THE FRAME SERVES TO FURTHER URGE SAID FIRST BAR INTO SAID GROOVE. 